When I was investigating a couple of "slow spots" on my layout with a voltmeter, I discovered that the maximum output from my CW-80 transformer is only 15 Volts.
The manual states 18V in one spot, and 16V somewhere else. The data plate on the bottom of the transformer states 18V.
Is it normal or do I have a dud?
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What kind of meter are you using to measure it? My understanding is that unless you are using a high dollar meter that can be set to measuring electronic transformers, most will actually read a lower voltage. So if you read 14-15V with the cheaper meters it is actually 18V. Since all I have is cheap meters, my 3 CW-80s are 12, 13, and 14V. I haven't measured my son's yet.
I'm using a ~15-year-old high-end Radio Shack digital meter. It certainly wasn't cheap when I bought it, >$100!
It reads the correct 18V when connected to an old "analog" 40W train transformer.
You may have a point about the digital meter / digital transformer thing... I seem to remember something about that.
I think the most I measured from mine was 15.5 volts using an average meter. I would say your measurement is normal. Of course its best to measure under load, running a train, to be most accurate.
There is lots of complicated circuitry inside the CW80. You can expect some voltage drop because of that. If you took it completely apart and measured directly from the transformer inside you would get a solid 18vac.
If you have "slow spots" you need to add power drops to those sections. A bigger/better transformer wont fix that.
According to a conversion chart I found posted on another board, a 12V reading on a vom expecting a sine wave (which would be most voms) corresponds to a CW-80 chopped output of 15.8V; 13V equals 16.6V; 14V equals 17.3V; 15V equals 17.9V; and 15.5V equals 18.2V. I believe this measurement should be taken with a load attached to the CW-80.
I used this info to set the accessory output of my CW-80 with my dvm.
Ok, that's good to know. Either we both have faulty transformers, or it's normal...
The only reason I noticed the "low" voltage was because I was checking the voltage drop at the slow spot on the loop, looking for the best place to add a drop.
I have a G0307 date code CW-80, it gets 16 volts open circuit and 16.2 volts with a 2 amp load on it.
Me to it says 15 volts too they are like that and a loud humming sound in my thought don't Get a second one get a Lionel power house with 180 wats. If you have command control? But if you have non commend get a mth z1000 with petty of power.
The Bob Nelson CW voltage deciphering chart for use with Harbor Freight & similar meters:
The RMS voltage should be 18 volts; but your meter should read a little more than 15 volts. Here is a chart for converting meter readings to RMS voltage:
Meter RMS
0 0
0.5 1.6
1 2.7
1.5 3.7
2 4.6
2.5 5.4
3 6.1
3.5 6.9
4 7.5
4.5 8.2
5 8.8
5.5 9.5
6 10
6.5 10.6
7 11.2
7.5 11.7
8 12.2
8.5 12.7
9 13.2
9.5 13.7
10 14.1
10.5 14.6
11 15
11.5 15.4
12 15.8
12.5 16.2
13 16.6
13.5 16.9
14 17.3
14.5 17.6
15 17.9
15.5 18.2
16 18.5
16.5 18.8
17 19
17.5 19.3
18 19.5
18.5 19.7
19 19.8
19.5 19.9
20 20
One problem is that your meter is designed to measure sine-wave AC voltage, which is not what the CW80 puts out. Nevertheless, a reading of 12 volts should mean that your actual RMS voltage is around 16 volts; so something else may be wrong. Are you giving the CW80 the full 120 volts that it probably expects? American power-line ("mains") voltage is often archaicly described as 110 volts, but hasn't been that low for over half a century. Your meter might also be a little off, which could explain some of the missing 2 volts.
Bob Nelson
It appears there is nothing wrong with your CW-80 if it is otherwise operating fine.
You should get close to a sine wave at full throttle with the CW-80. I admit I haven't 'scoped it yet, but other electronic controlled transformers look pretty close at full throttle.
Here you go:
If that's full throttle, that is pretty ugly! 
I'm not sure where he can say that power hasn't been that low for 50 years. I have a voltage meter plugged into my house and it reads around 111. I've had it at other places I've lived and ~110 has been what it reads. Even at work we base off of American power being 110 normally. Admittedly, the meter is way older than I am and could be off, but being off so perfectly as to read 110 is rather far fetched.
My power runs around 125V most of the time, I see it sag to as low as 120V occasionally on heavy usage days, and I've seen it as high as 130V at times as well. Currently, it's 127V on one leg and 128V on the other leg.
I have 120.2 volts right now. I've ever seen anything below 117 in 23 years here.
Guess I should stick my Harbor Freight special into the wall and see what it says I get. My house was built in the 60's and is in an even older part of town, so it's possible the power company keeps it lower here for safety reasons.
It wouldn't be a "safety" issue, the difference between 110VAC and 130VAC is minimal as far as danger involved.
If that's full throttle, that is pretty ugly!
The reason CW-80 doesn't play well with some other control systems. G
If that's full throttle, that is pretty ugly!
The reason CW-80 doesn't play well with some other control systems. G
I think that it's more the fault of the 'other' control system than any problem with the CW-80. Even some transformers made by that 'other' company are incompatible with some of their earlier products.
Right you are Nicole. I have had some PS/1 locomotives that won't run properly on the variable channels of the TIU, also some Lionel conventional models. I had one of the MTH wireless IR conventional lockons for testing, and it didn't like some conventional locomotives, including several of the PS/1 models.
Looking at the waveforms, I can see why the CW-80 is more problematic!
CW-80 with no load. The ringing goes away but the waveform stays the same with a 2 amp load. I missed getting that shot for some reason, don't feel like going back and doing it over.
TIU at full voltage out, looks pretty good. This doesn't change with the 2 amp load.
TIU at half voltage, again this doesn't change with the 2 amp load.
I notice in reading two of my Lionel loco manuals that it is stated that they are to be operated at between 7 to 15 volts. Recently, I had to have one loco's PC board replaced
and I 'speculate' that it may have been because I went up above that limit on one of
my CW-80's.
I use a Tegham brand electronic meter to check the outputs and all three of my xfmrs
around 16-17volts. Our cottage power where trains are is 125 + -.
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